﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine(gu(6));
            Console.ReadKey();
        }
        public static int gu(int i)
        {
            if(i==1)
            {
                return 1;
            }
            else
            {
                if(i%2==0)
                {
                    return  gu(i - 1)-i;
                }
                else
                {
                    return gu(i - 1)+i;
                }
            }
        }
    }
}
